Well I'm not sure this counts but I couldn't resist posting these look a likes , when I first saw these characters appearing in another anime , I was pretty surprised.

Shikamaru Nara from Naruto & Kageyama from Fairy Tail
Funnily enough they both use shadows for attacking.

Levi from Attack on Titan and Feitan from Hunter x Hunter (2011)

Don't think I've seen anyone post this one yet but when I saw this one I was like "Wow that's Levi allright" Must be their eyes.
Both characters are short and while techinically Levi is a badass , Feitan is more evil.